Multi-station simultaneous dual-side sanding machine

ABSTRACT

An adjustable automatic belt sanding machine wherein rectangular box-shaped workpieces requiring finish sanding of the four peripheral sides thereof are continuously fed through subsequent sanding stations of the machine in a line of top-to-bottom abutting workpiece relationship by means of a set of compressively engaging drive belts at the feed end of the machine, and thereafter each workpiece is progressively advanced and sequentially subjected to simultaneous coarse sanding of the respective opposing vertically machine oriented side surfaces thereof by a set of transversely spaced vertical sanding belts, afterwhich there is simultaneous coarse sanding of the upper and lower machine oriented side surfaces thereof by transversely spaced horizontal sanding belts, thereafter followed by simultaneous fine sanding of the aforementioned vertically oriented side surfaces by a second set of transversely spaced vertical sanding belts, and lastly, fine sanding of the aforementioned upper and lower side surfaces thereof by a second set of transversely spaced horizontal sanding belts, all of which enables the four-side finish sanding of box-shaped workpieces by a single pass of the workpieces through the machine.

United States Patent 1,1911

Rettew 1451 Sept. 30, 1975 1 1 MULTl-STATION SIMULTANEOUS DUAL-SIDESANDING MACHINE Richard L. Rettew, Newmanstown Pa.

[73] Assignee: Lek-Box, lnc., York, Pa.

[22] Filed: Sept. 4, 1974 [21] Appl. No.: 502,920

[75] Inventor:

354L735 11/1970 Sehaller et 211....

3562.961 2/1971 Clayson et a1. 51/138 3.566546 3/1971 Lindmark 51/142$845,588 11/1974 Huffman 51/140 Primary Examiner-Othcll M. SimpsonAllorney. Agent. or FirmC Hercus Just; Samuel M. Learned, Jr.

[57] ABSTRACT An adjustable automatic belt sanding machine whereinrectangular box-shaped workpieces requiring finish sanding of the fourperipheral sides thereof are continuously fed through subsequent sandingstations of the machine in a line of top-to-bottom abutting workpiecerelationship by means of a set of compressively engaging drive belts atthe feed end of the machine, and thereafter each workpiece isprogressively advanced and sequentially subjected to simultaneous coarsesanding of the respective opposing vertically machine oriented sidesurfaces thereof by a set of transversely spaced vertical sanding belts,afterwhich there is simultaneous coarse sanding of the upper and lowermachine oriented side surfaces thereof by transversely spaced horizontalsanding belts, thereafter followed by simultaneous fine sanding of theaforementioned vertically oriented side surfaces by a second set oftransversely spaced vertical sanding belts, and lastly fine sanding ofthe aforementioned upper and lower side surfaces thereof by a second setof transversely spaced horizontal sanding belts all of which enables thefour-side finish sanding of box-shaped workpieces by a single pass ofthe workpieces through the machine.

10 Claims, 4 Drawing Figures Sheet 1 of 3 3,908,316

f Sept 30,1975

US. Patent US. Patent Sept. 30,1975 Sheet 2 of3 3,908,316

I IL 'I] MULTI-STATION SIMULTANEOUS DUAL-SIDE SANDING MACHINE BACKGROUNDOF THE INVENTION It has long been a marketing technique to packageprestige products in correspondingly appropriate containers in order tocarry through a theme and sense which gives the consumer an outwardimpression as to the quality of the product packaged within thecontainer. In recent years, with the advent of an expanded male toiletryproduct market, one type of container which has come into popular andwide-spread use for packaging such products are various sizes and shapesof wooden boxes which are held together at the corners thereof by aplurality of glued mortice and tenon corner joints. In the constructionof such boxes it has been found necessary to sand down any protrudingtenon members or any other irregularities extending beyond both sides ofall four corners of said boxes and thereby bring the respectiveperipheral sides of said boxes and the connective corner joint elements,i.e., extending tenon members, into a smooth flush relationship with thebox sides.

Previously, the side-corner finishing operation as described supra hasbeen accomplished by an individual operator standing at a horizontal orvertical belt sanding machine, picking up and hand-holding one or moreboxes at a time with one side thereof in working contact with theoperating horizontal or vertical sanding belt of said machine, and thenin rotatable order, belt sanding each of the remaining three sides andextending corner elements of the box. The present invention relates to amachine designed to automatically accomplish the finishing operationsheretofore described and done by a single side, single unit at a timehandholding procedure.

Multiple station polishing and sanding machines have long been known,and, as is the case with the instant invention, such machines wereprimarily developed for accomplishing with greater speed, efficiency,and reduced material handling requirements which had formerly been doneby less productive means. The disclosure in U.S. Pat. No. 908,977 toDickson, dated Jan. 5, 1909, teaches an adjustable mechanical meanswhereby a workpiece manually inserted between a single set of transverseopposingly and inwardly rotating endless belts would enable thesimultaneous polishing of two opposite sides of said workpiece. However,the disclosure requires that an operator hand-hold and manipulate theworkpiece in order to employ the machine. No provisions are disclosedfor conveyance of multiple workpieces through said machine, nor is thereshown or claimed anything other than a single polishing stationcapability.

In U.S. Pat. No. 2,195,340 to Potash, dated Mar. 26, 1940, there isrevealed the incorporation of reciprocating shoe members to backup a setof transverse opposingly rotating sanding belts thereby impartingadditional abrading action upon the transverse sides of a .wooden slatworkpiece positively driven through the sanding station by a set of feedrollers. However, again, only two sides of a workpiece are operated uponby a single sanding station during a single pass through the machine,and, the machine is primarily designed to finish wooden slat workpiecesby sanding.

The employment of subsequent sanding stations in order to completelyfinish a workpiece with one pass LII through a machine is taught in U.S.Pat. No. 2,714,278 to Dostert, dated Aug. 2, 1955, which shows atransverse set of oppositely rotating sanding belts to finish thelongitudinal end faces of solid rod shaped workpieces as said workpiecesare rolled along a channel guide by drive belt means, thereafterfollowed by two nonopposing supplemental belt sanding stationsrespectively disposed at equally opposite angles, one to the other,whereby the periphery of each of the opposite end faces of said rodshaped workpieces are sequentially chamfered as said workpieces arerolled along said guide by said belt drive means. However, Dostertdiscloses a machine specifically designed and suited to a particularfinishing operation upon a particular geometrically shaped workpiece,namely cylindrical rods or pins. Further, Dostert does not teach asand-. ing station employing a set of transverse oppositely rotatinghorizontally disposed sanding belts.

In U.S. Pat. No. 3,178,860 to Clyne, dated Apr. 20, 1965, there istaught a multiple station sanding machine, however, disclosing singleside sanding of a workpiece only as the machine side which is transverseto each respective sanding head is occupied by a conveyor belt memberwhich is essential for transporting workpieces through said machine.Therefore, each side of a workpiece to be finished requires a separatepass through the machine.

Subsequently issued patents, such as the disclosures taught in U.S. PatNo. 3,269,065 to Nylund, dated Aug. 30, 1966, as well as in U.S. Pat.No. 3,541,735 to Schaller et al., dated Nov. 24, 1970, and U.S. Pat. No.3,654,738 to Sternal, dated Apr. 11, 1972, each teach certainimprovements and new and useful efficiency features in belt sandingmachines not previously disclosed or claimed, but none of which show noranticipate the instant invention, nor in combination would make theinstant invention obvious to one having ordinary skill in the art at thetime the instant invention was made. For example, Nylund teachesnon-simultaneous transverse side sanding of a workpiece whereby rollermeans are employed in order to apply abrading medium pressure to aworkpiece, as well as the art of partial cross-grain sanding of aworkpiece along the longitudinal dimension thereof. Schaller et alteaches the employment of variable oscillating non-aligned transverseabrading heads, i.e., abrading heads which are transversely opposed by abackup roll and not by another abrading head, thereby also resulting insuccessive but not simultaneous abrasion of opposite sides of aworkpiece. Sternal teaches high-speed transverse single pass sanding ofthe opposite sides of rough-sawn boards, employing also a partialcross-grain sanding technique as discussed in Nylund, but, however, bymeans wherein either the workpieces are fed through the machine at anangle to the longitudinal dimension of said workpieces, or thelongitudinal axes of the sanding heads are set at an angle off theperpendicular to the longitudinal dimension of the workpiece. Sternalalso teaches transverse reciprocation of the sanding belts as thesanding operation is beingperformed upon a workpiece.

The present invention is distinguishable from said earlier inventions inone or more ways in that the present invention has utility features andnew and useful advantages, applications, and improvements in the art ofbelt sanding workpieces not heretofore disclosed, as set forth below.

SUMMARY OF THE INVENTION It is the principal object of the presentinvention to provide a multi-station belt sanding machine wherein ahead-to-foot or top-to-bottom abutting line of mortice and tenon cornerjoint wooden or similar box-shaped workpieces are manually introduced toa horizontally disposed compressive feed belt conveyor by which saidworkpieces are engaged and positively impelled forward in longitudinalhead-to-foot or top-to-bottom compression through said machine alongguide members therein to subsequent laterally disposed vertical andhorizontal dual-belt sanding stations through which said workpieces aremoved and during transit therethrough respective rough and fine sandingof all four peripheral corners and sides of said workpieces aresequentially accomplished.

Another object of the present invention is to provide a multi-stationbelt sanding machine which will reduce workpiece handling requirementsby performing the finish sanding of all four corners and sides of saidworkpieces during only a single pass of said workpieces through saidmachine and effective vacuum removal of sanding wastes is accomplishedto provide efficiency and worker safety.

Still another object of the invention is to provide a multi-station beltsanding machine which is safe, relatively simple to adjust and operate,and may be set and run by an individual not possessed of specialmechanical skills or training.

A further object of the present invention is to provide a multi-stationbelt sanding machine which is easily and readily adjustable in thehorizontal and vertical direc tions in order to accommodate a wide rangeof different sizes of workpieces, which adjustments, once set, willretain dimensional stability throughout a production run.

Still another object of the invention is to provide a multi-station beltsanding machine which is designed to enable quick and easy changing ofsanding belts when said belts become worn.

It is yet another object to provide a multi-station belt sanding machinewherein the belt tension at each sanding station is continuouslymaintained at a constant value by pneumatic means mechanically linked tobelt tensioning members.

Details of the foregoing objects and of the invention as well as otherobjects thereof are described in the following specification andillustrated in the accompanying drawings comprising a part thereof.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevation of thesanding machine embodying the principles and features of the presentinvention.

FIG. 2 is a sectional top plan view of the machine shown in FIG. 1, asseen on the line 22 thereof.

FIG. 3 is an end view ofa transverse vertical sanding belt unit per seas shown in FIG. 1, as seen on the line 3-3 thereof.

FIG. 4 is an end view of a transverse horizontal sanding belt unit perse as shown in FIG. 2, as seen on the line 4-4 thereof.

DETAILED DESCRIPTION OF THE INVENTION Referring to FIG. 1, the presentinvention is shown which comprises a multi-station dual-side sandingmachine 10 having a supporting frame structure 12 com prised ofinterconnected horizontally and vertically disposed structural supportmembers, an infeed conveyor station 14 whereby workpieces are deliveredinto said machine 10 along guide rails 16 and sequentially impelled inhead-to-foot or top-to-bottom abutment through a dual vertical belt,coarse sanding station 18,

then through a dual horizontal belt, coarse sanding station 20,afterwhich said workpieces are moved through a dual vertical belt, finesanding station 22, and thereaf tcr through a dual horizontal belt, finesanding station 24 to the delivery table 26.

Also referring to FIG. 1 to explain the details of adjustment andoperation of the present invention, it will be seen that initially,depending upon the lateral side dimension of the box-shaped workpiecesto be run, the adjustable flexible compressive feed belt 28 of theinfeed conveyor station 14 is laterally moved in or out by rotating thefeed belt adjustment screw 30, by means of the feed belt adjustmentscrew handle 32 attached thereto, so as to compressively engage andconvey into the machine workpieces introduced into the infeed conveyorstation 14 between said adjustable flexible compressive feed belt 28 andthe stationary flexible compressive feed belt 34, said stationaryflexible compressive feed belts 28 and 34 being shown more particularlyin FIG. 2.

In making the infeed conveyor station 14 operational, adjustment is madefor accommodating the lateral dimension of said workpieces to be fedtherethrough. It is important that the compressive pressure exerted uponsaid workpieces fed between feed belts 28 and 32 within said infeedconveyor station 14 at any one time be sufficient to impel an abuttingline of headto-foot workpieces through said machine 10 along guide rails16 thereof to the delivery table 26 while sanding belt stations 18, 20,22, and 24 of said machine 10 are in operation, while at the same timenot resulting in slippage of said feed belts 28 and 34 across thecompressively engaged surfaces of said workpieces, nor cause damage toor distortion of said workpieces as a result of excessive compressivepressure resulting from an insufficient dimensional adjustment toaccommodate the lateral dimension of said workpieces.

In order to insure proper operational compressive feed-force adjustmentupon said workpieces, in accordance with the foregoing criterion, theinfeed conveyor station 14 is also provided with compressive driverollers 36, as well as compressive idler rollers 38, and infeed conveyorbackup plates 40, all of which function as backup members for flexiblecompressive feed belts 28 and 34 so as to limit the compressivedeflection of said flexible compressive feed belts 28 and 34, therebyenabling operational compressive feed-force adjustment upon saidworkpieces. In order to further control the infeed conveyor station 14,a variable-speed pneumatic motor 42 imparts controllable rotary motionto feed belts 28 and 34 drive rollers 36 by means of a chain drive 44 tosprocket 46 which, in turn, drives transmissions 48 through which rotarymotion is imparted to drive rollers 36 by which said feed belts 28 and34 are driven. Following the operational adjustment of said infeedconveyor station 14, the sanding belt stations 18, 20, 22, and 24 aredimensionally adjusted for workpieces to be run. Since the two verticalbelt sanding stations 18 and 22 are identical in all operationalrespects, excepting for the abrasive grades of sanding belts affixedthereto, as are also the two horizontal belt sanding stations and 24,only one of each type station, namely 18 and 20, will be described indetail, it being understood that the respective corresponding sandingstations 22 and 24 are identical excepting only for the finer abrasivegrade of the sanding belts affixed thereto.

Dimensional adjustment of the vertical sanding belt stations 18 and 22to accommodate the machine oriented lateral sides of workpieces to befed therethrough, is accomplished by rotating the vertical belt sandingstation adjustment handle 50, which moves the operator-side verticalsanding belt member 52, by means of the vertical belt adjustment screw54, as well as the guide rail member 16 attached thereto, laterally inor out. It will be understood that dual vertical belt, fine sandingstation 22 will be set at a dimensional adjustment slightly less thandual vertical belt coarse sanding station 18 as the majority of materialto be removed from the lateral sides of said workpieces will have beenaccomplished during passage thereof through coarse sanding station 18.

Initial lateral adjustment of belts 52 and 53 may be made in terms ofdimension by measuring the lateral distance between the stationaryvertical sanding belt member 53 and the adjustable operator-side sandingbelt member 52 by means of the side guide belt and guide rail dimensionindicator 56, see FIG. 2. However, final dimensional adjustment betweenvertical belts 52 and 53 is made by the operator, and is primarilydependent upon the amount of material to be sandably removed from theworkpieces, as well as any other operational factors and considerationsto be taken into account. Additionally, vertical holddown guide 58 shownin FIG. 1 is set to retain said workpieces in stable position duringtransit through dual vertical sanding belt stations 18 and 22.

Centering and control of vertical belt members 52 and 53 upon therespective vertical belt drive rollers 60 and vertical idler rollers 62is by means of a belt guide dog 64 whichis adjustable for purposes ofcentering vertical belt members 52 and 53 by means of the belt trackingadjustment assembly 66 shown in FIG. 2. It should be understood that alladjustments and settings of vertical belt members 52 and 53 areaccomplished while said belt members 52 and 53 are under tension, whichtension is consequent from extension of an air cylinder piston rod 68connectably linked to vertical belt idler rollers 62, whereby said idlerrollers 62 are held in extension by said air cylinder 70, therebyproviding means to maintain a constant belt tension. When vertical beltmembers 52 and 53 are to be changed, said air cylinder piston rod 68 isretracted, thereby releasing belt tension, and enabling quick and easyremoval of worn vertical belt members 52 and 53 and replacement of newvertical belt members 52 and 53, after which air cylinder piston rod 68is extended, thereby regaining a constant tension on vertical beltmembers 52 and 53. Additionally shown as elements of the dual verticalbelt sanding stations 18 and 22 are vertical belt drive motors 72 andvertical belt station vacuum system collectors 74 for sanding dust.

Dimensional adjustment of the horizontal belt sanding stations 20 and24, in order to accommodate the machine oriented upper and lower sidesof workpieces to be fed therethrough, is accomplished by essentially thesame methods, means, and technique as is used to adjust the verticalbelt sanding stations 18 and 22, namely, the horizontally adjustablesanding belt member 76 is raised or lowered in relation to thestationary horizontal sanding belt member 78 by means of rotating thehorizontal belt sanding station adjustment handle 80, which in turnrotates the horizontal belt adjustment screw 82, whereby saidhorizontally adjustable sanding belt member 76 is elevated or depressedin order to accommodate the vertically machine-oriented dimension ofworkpieces to be fed therethrough. Initial setting of said horizontallyadjustable belt member may be measured by means of the top guide beltand guide rail dimension indicator 84 shown in FIG. 1. However, as withthe operational setting of the vertical belt members, final dimensionaladjustment between horizontal belts 76 and 78 is made by the operator inaccordance with and dependent upon the operational factors to beconsidered in finishing a particular type, size, and run of workpieces.

Again, it will be understood that the dimensional setting on the finehorizontal sanding belt station 24 will be dimensionally slightly lessthan the setting at the coarse horizontal sanding belt station 20 as themajority of material to be removed from the upper and lower sides ofworkpieces will have been accomplished during passage thereof throughcoarse horizontal sanding station 20. Upon operational adjustment ofhorizontal sanding belt members 76 and 78, as heretofore explained,which is also accomplished under tension from air cylinder 70, thehorizontal side retaining guides 86 are adjusted to stabilize theworkpieces as they are transported through horizontal sanding beltstations 20 and 24.

As with the earlier described vertical sanding belt stations 18 and 22,the horizontal sanding belt stations 20 and 24 likewise have ascomponent elements thereof horizontal belt drive rollers 88 connected tohorizontal belt drive motors 90 and horizontal belt idler rollers 92around which rollers 88 and 92 the horizontal belt members 76 and 78rotate. Horizontal belt guide dogs 94, adjusted by means of horizontalbelt tracking adjustment assembly 96, provide the means wherebyhorizontal sanding belt members 76 and 78 are adjusted, centered, andmaintained in position upon the horizontal belt drive rollers 88 and theidler rollers 92 during operation. Also, as with the vertical sandingstations 18 and 22, horizontal sanding stations 20 and 24 include belttension means provided by extension of an air cylinder rod 68connectably linked to horizontal belt idler rollers 92, whereby saididler rollers 92 are held in extension by aforementioned air cylinder70, thereby providing means to maintain constant horizontal belt 76 and78 tension. Retraetion of said air cylinder piston rod 68 releasestension on belts 76 and 78, whereby said belts 76 and 78 may be removedand replaced by new belts or belts having different sanding properties.Upon the installation of new belts said piston rod 68 is extended andtension on said belt members 76 and 78 is re-established. Additionallyincluded as a component element of horizontal belt sanding stations 20and 24 are horizontal belt station vacuum system collectors 98 forsanding dust.

The multi-station dual-side sanding machine 10 thus far described isoperationally set to run a particular lot of similar workpieces to whichdimensional adjustment has been made in the machine. workpieces arethereafter aligned in an abutting head-to-foot or top-to-bottomconfiguration on the staging conveyor 100 which is driven by a belt 102attached to a pulley 104 on the drive shaft of variable-speed pneumaticmotor 42. It should be noted that all electrical functions of themachine are operated from control panel 106., whereas all pneumaticfunctions, such as those of variable-speed pneumatic motor 42 and aircylinders 70, are controlled by standard regulators and valves connectedto the plant air supply, none of which are shown in the drawingsincluded herewith since the same are of conventional nature.

The machine 10 as disclosed in FIG. 1 preferably is constructed ofmetal, but any other suitable materials or combinations thereof may beused.

Referring to FIG. 2, which is a sectional top view of the side elevationof the machine shown in FIG. 1 as seen along the line 2--2 thereof,there is shown more specifically the configuration of component elementsof the machine as heretofore described. Principally shown in moreparticular detail is the plan relation and arrangement of infeedconveyor station 14 and the elements thereof.

In FIG. 3, an end view per se of the vertical sanding station 18 isshown as seen along the line 3-3 of FIG. 1. Additionally shown, however,is an exemplary workpiece 108 and the manner by which said workpiece 108is supported in the sanding zone of sanding station 18 by guide rails16. It will be noted that guide rails 16 have support lips which extendunder the lower surfaces at opposite sides of said workpiece 108,thereby providing the necessary support to maintain said workpiece 108in vertical alignment against the pushing effects of inwardly rotatingvertical sanding belt members 52 and 53. It should be noted, however,that the guide rail members are interrupted within the sanding zone, toaccommodate the sanding belts thereby enabling the respective beltmembers to be flush with the opposing vertical sides of workpieces assaid workpieces are sanded and transported through said sanding zone.Also shown to advantage in FIG. 3 are the vertical sanding belt backupplates 110 which provide lateral support to workpiece 108 shown withinthe sanding zone. Also shown, as heretofore described, is verticalholddown guide 58 which provides stabilizing support to said workpiece108 in the vertical station 18 sanding zone by being slidably engaged bythe workpieces 108.

Additionally shown in more detail are certain of the structural supportelements for the vertical sanding station roller and belt assemblies. Inparticular, support rods 114 for the vertical belt adjustment means areshown, along which the frame which supports the adjustable verticalsanding belt member 52 is slidably guided and moved during a lateralincrease or decrease of the transverse dimension of the sanding zone,and also by which said sanding belt member is held securely in positionduring sanding operations. Also shown are the lateral support arms 116for the belt member backup plate, which not only provide the backupplate mounting means, but also include connection means 118 forpivotally attaching the air cylinders 70 which provide the tensioningmeans for belt members 52 and 53 through pivotal engagement and movementof the belt tensioning lever arm 120 upon extension of the air cylinderpiston rod 68. Support plate members 122 are the structural means in thevertical sanding belt station 18 by which the drive and idler rollersare securely supported for rotation about fixed axes to support belt 53and relative to which the supporting means for belt 52, described above,are mounted for adjustment toward and from belt 53.

The entire vertical sanding belt station end view assembly, as shown inFIG. 3, is positioned within and securely affixed to and supported bythe vertical frame member 126 and horizontal frame member 128 of thesupporting frame structure shown in FIGS. 1 and 2,

which frame attachment and support members form mechanical enclaveswithin which said sanding station assemblies are enclosed, but however,for purposes of drawing clarity, said enclave assembly has not beenshown in FIG. 3. All other elements seen in FIG. 3 are as heretoforedescribed, except as seen in end view.

In FIG. 4 an end view per se of the horizontal sanding station 20 isshown as seen along the line 44 of FIG. 2. Also additionally shown,however, is an exemplary workpiece 108 as seen in FIG. 3, but revealinghow said workpiece 108 is supported in said sanding station 20 sandingzone by horizontal guide rail sections 16. It will be noted thathorizontal guide rails 16 have longitudinal support lips extending aboveand below the outboard lateral surface of the workpiece 108, therebyproviding the necessary support to maintain said workpiece 108 inhorizontal alignment against the pushing effects of outboard rotatinghorizontal sanding belt members 76 and 78. Again, it should be notedthat the guide rail members are interrupted within the sanding zone,thereby providing spaces to enable the respective belt members to beflush with the opposing horizontal sides of workpieces as saidworkpieces are sanded and transported through said sanding zone. Alsoadditionally shown to advantage in FIG. 4 are horizontal sanding beltbackup plates 112 which provide vertical support to workpieces 108 whenwithin the sanding zone. Further shown, as heretofore described, ishorizontal holddown guide 86 which provides stabilizing support to saidworkpiece 108 in the horizontal station 20 sanding zone.

Additionally shown in FIG. 4 are the support rods 124 for the horizontalbelt adjustment means along which the frame which adjustably supportsthe horizontal sanding belt member 76 is slidably guided and movedduring a vertical increase or decrease of the vertical dimension of thesanding zone of sanding station 20, and by which said sanding beltmember also is held securely in position during sanding operations. Alsoshown, as heretofore described in the description of FIG. 3, are thehorizontal support arms 116 for the belt member backup plate, as well asthe pivotal connection. 118 for air cylinder and the tensioning leverarm 120, as well as the respective stationary and adjustable horizontalsupport plate assemblies 122 for sanding belt 76 which is verticallyadjustable relative to belt 78 which is non-adjustable. As with thestructure in FIG. 3, the supporting frame structure of said machine hasnot been shown for purposes of clarity of the drawing. It will, however,be understood that the descriptions of said frame structure heretoforegiven are equally applicable as regards mounting and support of the unitdepicted and described by FIG. 4. All other elements seen in FIG. 4 areas heretofore described, except as seen in end view.

While the invention has been described and illustrated in its severalpreferred embodiments, it should be understood that the invention is notto be limited to the precise details herein illustrated and describedsince the same may be carried out in other ways falling within the scopeof the invention as illustrated and described.

I claim:

1. A sanding machine having a supporting frame structure ofinterconnected vertical and horizontal frame members to support unitsthereof adapted to sand the four peripheral sides of a plurality ofhead-tofoot abutted rectangular shaped objects during a single pass ofsaid objects through said machine comprising in combination, a laterallydisposed compressive infeed conveyor means by which opposite sides ofsaid objects are compressively engaged in abutting head-to-footrelationship one to the other and impelled unidirectionally from thefeed end to the delivery end of said machine along an elongated seriesof guide members having horizontal supporting surfaces extending fromthe feed to the delivery ends of said machine to provide a path alongwhich said objects are slidably supported in said head-to-foot abuttingrelationship to each other during movement through said machine, a firstsanding unit comprising a pair of opposed endless sanding belts havingparallel vertical courses disposed adjacent opposite sides of said guidemembers and operable simultaneously to sand opposite lateral faces ofsaid objects, horizontal guide means laterally disposed below the lowersurfaces of said abutted objects to resist downward deflective movementtherof from the plane of said guide members, a second sanding unitcomprising another pair of opposed endless sanding belts havingvertically spaced parallel horizontal courses respectively above andbelow the other pair of opposed surfaces of said objects as moved alongsaid guide members, said guide members being interrupted to accommodatesaid courses of said horizontal belts above and below said objects,perpendicular guide means adjacent one side of said guide membersbetween said horizontal courses of said another pair of belts to permitsaid objects to resist lateral movement from said guide members in thedirection of movement of said courses of said horizon tal belts, andsupporting frame means supporting all of said conveyor means and guidemembers in association with said first and second sanding units.

2. The sanding machine according to claim 1, in which said supportingframe means is provided with adjustable means operable to effectadjustable spacing of the infeed conveyor means and sanding belts ofsaid sanding units.

3. The sanding machine according to claim 1, in which the compressiveinfeed conveyor means comprises a pair of feed belts operable invertical planes having parallel inwardly moving courses at oppositesides of the feed-end of said machine to impel said objects in feedingdirection in succession to and through said sanding units.

4. The sanding machine according to claim 1, wherein each respectivevertiical and horizontal sanding belt member of the respective verticaland horizontal pairs of sanding belts extend around pairs of spacedrollers supported by elongated parallel plate members, the first rollerof which is a drive roller and the second roller is an idler roller,each axis of rotation of said idler roller being mechanically linked toa separate pneumatic cylinder means mechanically affixed to a separatesupporting frame member of said machine, whereby pneumatic extension ofa piston of each of said pneumatic cylinder means distends said idlerroller and tensions each of said vertical and horizontal sanding beltmembers of said vertical and horizontal pairs of sanding belts.

5. The sanding machine according to claim 1, wherein each pair ofvertical and horizontal belts extending around pairs of spaced drive andidler rollers respectively comprise a stationary belt member assemblyand an adjustable belt member assembly, said adjustable belt memberassembly being slidably mounted upon guide rods supported upon the frameof said machine, and means operable to move said adjustable belt memberassembly upon said rods toward or away from said stationary belt member.

6. The sanding machine according to claim 1, wherein said adjustablevertical and horizontal sanding belt members of each sanding unit aresubstantially the same, said belts are mounted upon a support platemember transverse to the stationary sanding belt members, said supportplate members are adjustable by screw means and mounted vertically forhorizontal sanding belt adjustment and horizontally for vertical sandingbelt adjustment.

7. The sanding machine according to claim 1, further provided with gaugemeans for both the adjustable vertical and horizontal sanding beltmembers to indicate the dimensional spacing of said adjustable verticaland horizontal sanding belt members from the respective stationaryvertical and horizontal sanding belts members.

8. A sanding machine according to claim 1, adapted to sand the fourperipheral sides of a plurality of headto-foot aligned and abuttedrectangular shaped objects during a single pass of said objects throughsaid machine and further including a geometrically configured sandingdust collection hopper positioned below each of the inward rotatingvertical pair of sanding belts, and vacuum means attached to said hopperby which particulate matter abrasively removed from the peripheralvertical sides of the plurality of rectangular shaped objects during thesanding operation is captured and conveyed therefrom to collectionmeans.

9. A sanding machine according to claim 1, adapted to sand the fourperipheral sides of a plurality of headto-foot abutted rectangularshaped objects during a single pass of said objects through said machineand further including a geometrically configured sanding dust collectionhopper vertically positioned at the end opposite the inward rotatingdirection of each of the horizontal pair of sanding belts and having avertically disposed extension underlying the lower belt member thereof,and dual vacuum means connected thereto by which particulate matterabrasively removed from the peripheral horizontal sides of the pluralityof rectangular shaped objects during the sanding operation is capturedand conveyed therefrom to collection means.

10. A sanding machine according to claim 1, adapted to sand the fourperipheral sides of a plurality of headto-foot abutted rectangularshaped objects during a single pass of said objects through said machineand wherein the guide members of said machine are I..- shaped incross-section and are positioned to slidably support said objectsagainst downward movement during transfer of said objects through pairsof vertical sanding belts and also laterally support said objects duringtransfer of said objects through pairs of horizontal sanding belts.

1. A sanding machine having a supporting frame structure ofinterconnected vertical and horizontal frame members to support unitsthereof adapted to sand the four peripheral sides of a plurality ofhead-to-foot abutted rectangular shaped objects during a single pass ofsaid objects through said machine comprising in combination, a laterallydisposed compressive infeed conveyor means by which opposite sides ofsaid objects are compressively engaged in abutting head-to-footrelationship one to the other and impelled unidirectionally from thefeed end to the delivery end of said machine along an elongated seriesof guide members having horizontal supporting surfaces extending fromthe feed to the delivery ends of said machine to provide a path alongwhich said objects are slidably supported in said head-to-foot abuttingrelationship to each other during movement through said machine, a firstsanding unit comprising a pair of opposed endless sanding belts havingparallel vertical courses disposed adjacent opposite sides of said guidemembers and operable simultaneously to sand opposite lateral faces ofsaid objects, horizontal guide means laterally disposed below the lowersurfaces of said abutted objects to resist downward deflective movementtherof from the plane of said guide members, a second sanding unitcomprising another pair of opposed endless sanding belts havingvertically spaced parallel horizontal courses respectively above andbelow the other pair of opposed surfaces of said objects as moved alongsaid guide members, said guide members being interrupted to accommodatesaid courses of said horizontal belts above and below said objects,perpendicular guide means adjacent one side of said guide membersbetween said horizontal courses of said another pair of belts to permitsaid objects to resist lateral movement from said guide members in thedirection of movement of said courses of said horizontal belts, andsupporting frame means supporting all of said conveyor means and guidemembers in association with said first and second sanding units.
 2. Thesanding machine according to claim 1, in which said supporting framemeans is provided with adjustable means operable to effect adjustablespacing of the infeed conveyor means and sanding belts of said sandingunits.
 3. The sanding machine according to claim 1, in which thecompressive infeed conveyor means comprises a pair of feed beltsoperable in vertical planes having parallel inwardly moving courses atopposite sides of the feed-end of said machine to impel said objects infeeding direction in succession to and thRough said sanding units. 4.The sanding machine according to claim 1, wherein each respectivevertiical and horizontal sanding belt member of the respective verticaland horizontal pairs of sanding belts extend around pairs of spacedrollers supported by elongated parallel plate members, the first rollerof which is a drive roller and the second roller is an idler roller,each axis of rotation of said idler roller being mechanically linked toa separate pneumatic cylinder means mechanically affixed to a separatesupporting frame member of said machine, whereby pneumatic extension ofa piston of each of said pneumatic cylinder means distends said idlerroller and tensions each of said vertical and horizontal sanding beltmembers of said vertical and horizontal pairs of sanding belts.
 5. Thesanding machine according to claim 1, wherein each pair of vertical andhorizontal belts extending around pairs of spaced drive and idlerrollers respectively comprise a stationary belt member assembly and anadjustable belt member assembly, said adjustable belt member assemblybeing slidably mounted upon guide rods supported upon the frame of saidmachine, and means operable to move said adjustable belt member assemblyupon said rods toward or away from said stationary belt member.
 6. Thesanding machine according to claim 1, wherein said adjustable verticaland horizontal sanding belt members of each sanding unit aresubstantially the same, said belts are mounted upon a support platemember transverse to the stationary sanding belt members, said supportplate members are adjustable by screw means and mounted vertically forhorizontal sanding belt adjustment and horizontally for vertical sandingbelt adjustment.
 7. The sanding machine according to claim 1, furtherprovided with gauge means for both the adjustable vertical andhorizontal sanding belt members to indicate the dimensional spacing ofsaid adjustable vertical and horizontal sanding belt members from therespective stationary vertical and horizontal sanding belts members. 8.A sanding machine according to claim 1, adapted to sand the fourperipheral sides of a plurality of head-to-foot aligned and abuttedrectangular shaped objects during a single pass of said objects throughsaid machine and further including a geometrically configured sandingdust collection hopper positioned below each of the inward rotatingvertical pair of sanding belts, and vacuum means attached to said hopperby which particulate matter abrasively removed from the peripheralvertical sides of the plurality of rectangular shaped objects during thesanding operation is captured and conveyed therefrom to collectionmeans.
 9. A sanding machine according to claim 1, adapted to sand thefour peripheral sides of a plurality of head-to-foot abutted rectangularshaped objects during a single pass of said objects through said machineand further including a geometrically configured sanding dust collectionhopper vertically positioned at the end opposite the inward rotatingdirection of each of the horizontal pair of sanding belts and having avertically disposed extension underlying the lower belt member thereof,and dual vacuum means connected thereto by which particulate matterabrasively removed from the peripheral horizontal sides of the pluralityof rectangular shaped objects during the sanding operation is capturedand conveyed therefrom to collection means.
 10. A sanding machineaccording to claim 1, adapted to sand the four peripheral sides of aplurality of head-to-foot abutted rectangular shaped objects during asingle pass of said objects through said machine and wherein the guidemembers of said machine are L-shaped in cross-section and are positionedto slidably support said objects against downward movement duringtransfer of said objects through pairs of vertical sanding belts andalso laterally support said objects during transfer of said objectsthrough pairs of horizontal sanding belts.